Washington State Ferries has submitted a plan to convert six ferries to run on liquefied natural gas to the U.S. Coast Guard. WSF says the conversion would save them money on fuel costs and reduce emissions.

The proposal, to convert six Issaquah Class ferries to run on liquefied natural gas, follows more than three years of study, according to a press release from the Washington State Department of Transportation.

WSF submitted its proposal to the Coast Guard Nov. 18 in a formal letter of intent and waterways suitability assessment, according to the release. It marks the official starting point of the Coast Guard’s review process, according to the release. WSF expects a finding from the Coast Guard in 2014.